Connection device for electric cables



April 29, 1969 N. l. NQDF'ELT 3,441,898

CONNECTION DEVICE FOR ELECTRIC' CABLES Filed April e, 1967 l sheet of 2e e 214 41u 4a 4b`51`d153 sq? 1C 1b 7 1d 5 5G 10 8 7'G1C l l l l FIG.3

April 29, 1969 N. I. NODFELT CONNECTION DEVICE FOR ELECTRIC CABLES sheet2 @f2 Filed April 6, 1967 Nwe, l.

United States Patent O 3,441,898 CONNECTION DEVICE FOR ELECTRIC CABLESNils Ingvar Nodfelt, Jarnvagsgatan 76, Gnosjo, Sweden Filed Apr. 6,1967, Ser. No. 628,901 Int. Cl. H01r 31/02, 7/06 U.S. Cl. 339-48 4Claims ABSTRACT OF THE DISCLOSURE Background of invention (1) Theinvention refers to a device for connecting electric cables, preferablyof the multiconnector type, and is especially suited for use withelectronic apparatuses where it is desirable that the transferresistance shall be low.

(2) Connection `devices of known type usually are provided with matingmale and female contact members. In the present device two male membersare mating.

Summary The invention is essentially characterized by each member havingan oblique contact end surface and an intermediate portion havingflattened surfaces to form a strip shaped bar, the plane of this bar andthe plane of oblique front end surface both being perpendicular to thesame axial plane of the contact member. The contact members of onecoupling part are slightly off-set in relation to those of the othercoupling part so that as the parts are tightened together, the obliquecontact surfaces slide against each other to move the contact memberssidewards.

The members are fitted into bodies of insulating material which areprovided with axially protruding ridges encircling the members andadapted to seal off the contact area from the ambient atmosphere.According to a development of the idea the insulating body is designedto receive the individual members in such a manner that any damagedmember may be easily exchanged.

Brief description of the drawings Description of the preferredembodiments For the sake of simplicity only the essential componentshave been indicated.

FIGURE 1 shows a contact member 1 employed in the connection deviceillustrated in FIGURES 2 and 3. Each member has a cylindrical front endportion 1a and a back portion 1b the last mentioned being provided with3,441,898 Patented Apr. 29, 1969 "ice a part-tubular portion 1c adaptedto be connected to a conductor (not shown in FIGURE 1). The end portions1a and 1b are interconnected by a narrow flat strip or band shapedportion 1d which has a width corresponding to the ydiameter of the rstmentioned end portion. This intermediate portion makes an elasticdeformation of the member possible The dimensions of the strip portionare, however, such that any fbending in a direction parallel to saidplane is prevented. The front end surface 1e :of the front end portion1a is obliquely arranged with respect to the longitudinal axis of themember and is designed to slide against a correspondingly shaped contactsurface 1e of an adjacent member, when the two contact members arebrought together into contact. During this contact operation the frontend portion 1a of the engaging mem-bers are deflected by the elasticdeformation of the strip-shaped intermediate portions 1d.

The connection device illustrated in FIGURE 2 consists of two couplingparts 2 and 3 respectively, the com ponents of each part beingessentially alike. Each part 2 and 3 consists of a tubular casing 4provided with unsymmetrically arranged ridges 4a and 4b which make aconnection of the two parts 2 and 3 possible in one relative positiononly. The ends of the casings carrying these ridges and recesses haveinner and outer diameters which are slightly larger than the ends of thecasings remote from the connection. These enlarged portions of thecasings 4 are provided with front end inserts 5 of dielectric andelastic material, preferably rubber. Each insert 5 is .provided withseven axially directed passages as shown in FIGURE 3, each adapted totightly enclose the front end portion 1a of a contact member. Theadjacent end surfaces of the inserts 5 are each provided with an annularridge 5a. In order to prevent moisture from entering the connectingmember said ridges are designed to be brought into close contact witheach other when the two contact members of the connecting device areconnected. The elastic rubber inserts 5 ensure that the end portions ofthe contact members are held in definite rest positions and permit asideways movement during the connection operation of the contact member.

In order to retain the contact members in proper axial positions, whichis diflicult to achieve solely by front rubber inserts 5, the end ofeach casing 2, 3 remote from the connection joint is provided with aback end insert 6 of comparatively hard synthetic resin, into which theback ends 1b of the members are forced. Each insert 6 is provided withan annular flange 6a at about its middle portion which flange 6a isadapted to rest against the outer end of the casing 4. The -llange islocked against casing 4 by a threaded sleeve 7 provided with a flange 7acooperating with flange 6a through a packing 8.

The coupling parts are retained in tted position bymeans of tubularmembers 14, 15. Member 14 is freely rotatable about the coupling part.They co-operate at their outer ends with anges thereon and are threadedat their meeting portions.

As shown in FIGURE 2, the end portions of the contact members, in theirrest position, are somewhat offset in relation to each other. During theconnecting operation the oblique contact surfaces will slide upon eachother While forcing the top parts of the contact members sidewaysagainst the action of the rubber inserts 5 and the resiliency of themem-bers. During this sliding movement any possible oxide coating on thecontact surfaces will be removed and a continued good contact betweenthe members is ensured by the resiliency. As each member consists of asingle part only the total transfer resistance between the contactingends of the cables joined by the conecting means will be insignificant.The risk of oxidation of the connected contact members is comparativelysmall, since the contact surfaces of the members is completely protectedfrom the influence of the atmosphere by the ridge portions 5a of therubber inserts.

In the modied connection device shown in FIGURE 4 the member 1, in thesame manner as shown in FIG- URES 1-3 is provided with a cylindricalfront end portion 1a and a cylindrical back end portion 1b. The lastmentioned portion is provided with an elongated sleeve portion 1cadapted to enclose a conductor (not shown). The end portions 1a, 1b areinterconnected by a flat strip or band-shaped intermediate portion 1a'.The front end portion is provided with an oblique contact surface 1e.

The connection device consists of two contact members each containing aninsert 6 of dielectric material, for instance a comparatively hardsynthetic resin. The insert 6 is provided with the appropriate number ofpassages 9, of which one only is shown in FIGURES 4 and 5. In the middlepart of each passage a ridge 10 is arranged. The back end portion 1b ofthe Contact member is provided with a transverse recess 11 adapted toco-operate with said ridge 10. The contact member is shaped to beretained within the passage 9 by its own resiliency. The planes ofrecess 11, the at strip or bandshaped intermediate portion 1d and theoblique contact surface 1e are perpendicular to the same axial plane thelongitudinal axis of the contact member. The free opening 12 between thetop of the ridge 10 and the opposite wall of the passage 9 is slightlylarger than the cross sectional area of the front end portion of thecontact member.

The contact member 1 is inserted in the passage 9 with the pointed frontend portion 1a first and is pushed inwards until the recess 11 enclosesridge 10. By the form of the member an eicient locking is obtained, themember contacting the passage at three points A, B and C respectively.When the parts 2 and 3 of the connection member are brought together theoblique contact surface 1e of one member will be forced against thecorresponding surface 1e of the adjacent member. During this operationthe contact in point C is released while the pressure of the memberagainst the ridge (point B) is increased. When it is desired to replacea contact member an oblong tool is inserted behind the member, i.e.between the side of the member which extends towards the lip of theoblique surface. By means of this tool the end portion `1b may be movedagainst the action of the resiliency of the member suciently to makepossible a release of recess 11 from the ridge 10 so that the member maybe removed.

What I claim is:

1. In a connection device for electric cables including two couplingparts adapted to be connected together, each coupling part comprising ofa body of insulating material and at least one rod-like contact membercarried thereby in a position to mate with a' juxtaposed member in theopposite coupling part, said members at their back ends being connectedto conductors in the cables, said members each including an obliquecontact front end surface for contacting a corresponding front endsurface of the juxtaposed member and an intermediate portion of eachmember having attened surfaces on its opposite sides to form a narrowstrip-shaped bar,

the member in one coupling part being slightly olf-set in relation tothe juxtaposed member in the other coupling part so that as the twocoupling parts are tightened together, the oblique Contact Surfacesslide against each other and elastically bend the contact members.

2. A connection device according to claim 1 in which the insulating bodyof each coupling part is provided with an axially protruding ridgeencircling the contact members supported by the body and designed to bebrought into sealing contact with the juxtaposed ridge of the othercoupling part.

3. A connection device according to claim 1 in which the insulating bodyincludes of a back portion for rigidly supporting the back ends of thecontacts members and a front portion enclosing the front ends of thecontact members, said front and back portions being connected by atubular member leaving the intermediate portion of the members free.

4. A connection device according to claim 1 in which the individualcontact members are located in bores in a comparatively rigid body ofinsulating material, there being a recess in the back end portion of themember and a correspondingly shaped ridge in the wall of the bore, thefree opening between the ridge and the opposite wall of the bore beingslightly larger than the cross sectional area of the front end portionof the member.

References Cited UNITED STATES PATENTS 397,553 2/1889 Johnston 339-49 XR2,572,448 10/ 1951 Child. 2,638,573 5/1953 Glickman et al. 2,972,7282/1961 Cole 339-64 3,185,955 5/1965 Keller 339-91 MARVIN A. CHAMPION,Primary Examiner. PATRICK A. CLIFFORD, Assistant Examiner.

U.S. Cl. X.R.

